The invention concerns a solar furnace, more particularly a furnace constructed of elements designed to maximize internal temperatures attainable from solar radiant energy.
With the escalating costs of fossil energy sources, solar energy is becoming ever more attractive. Solar radiation itself, of course, is free. The cost of the equipment required to transform solar energy to useful applications stabilizes the total cost of this energy source at the cost of construction, thereby avoiding the price increases which seem to be an inevitable part of fossil energy sources. Further, with appropriate design solar energy can be converted to useful application at significant cost savings over the present cost of fossil energy. For these and other reasons, then, solar energy systems are projected to provide over 60% of today's energy requirements in the year 2020.
Various collectors of solar energy have been designed. Uniformly, they are designed to make more effective use of solar energy. Some are intended to satisfy household heating requirements; others are capable of, or designed for, other uses. In U.S. Pat. No. 3,000,375 issued to Marcel Golay on Sept. 19, 1961 an evacuated heat absorbent body, or block, is described. This block, apparently constructed of glass, is evacuated or filled with a gas of low thermal conductivity. In the lower portion of the block, or on its base, is a polished reflective base plate that bears a thin film of a semiconductive black coating, such as of tellurium, positioned to receive solar radiation. While such a structure certainly is useful, it is costly to fabricate, in large part because of construction of the base plate and its evaporated coating. This in turn significantly constrains the applications in which it can be used, and limits its cost effectiveness when compared as an energy source with the various conventional fossil fuel energy sources.
It would be highly desirable to provide a solar furnace, and solar heating elements, of economic construction that would provide a solar energy source that, at maximum, would be no more expensive than the cost of other, conventional fossil fuel energy sources. Further, it would be desirable to provide such elements as part of a solar furnace, capable of obtaining and maintaining temperatures of 200.degree. C. and above for extended periods. Also, an effective insulator is necessary to contain and conserve energy, whether of a solar or fossil source, and in a furnace or elsewhere. These and other objects of the invention will be apparent to those skilled in this art from the following description.